sept, n, 19 io Bacteriological Studies of a Soil 955 



30 are of a slightly different texture, being located on the western slope 

 of the same rise. For this reason they are omitted from the general 

 scheme and are compared with each other only. The greatest distance 

 between any two plots (No. 1 and 23) is only about 85 yards. It was 

 impossible to get the specially treated plots that we wished to study 

 located any closer together. It is not believed, however, that any differ- 

 ence due to character of soil, location, etc., could materially affect the 

 major differences reported. The plots studied, treatment received, and 

 yields are given in Table I. It will be noted that the plots studied during 

 1 91 4 varied somewhat from those of the previous year. This was neces- 

 sary because of a change in treatment in certain plots beginning in 1914. 

 In the tabulated data, plot 1 always includes the data obtained from 

 plot 20 (a duplicate). Similarly plot 10 includes data secured from 

 plot 21 (a duplicate). 



Where stable manure has been applied, it has been an annual appli- 

 cation averaging 6.7 tons per acre on all plots except No. 1, which re- 

 ceived 7 tons. The chemicals were applied annually on plots 2 and 3 in 

 the form of sodium nitrate, potassium chlorid, and acid phosphate in 

 quantities sufficient to supply nitrogen, potassium, and phosphorus for 

 a full yield of the particular crop. In the case of wheat this was for a 

 yield of 40 bushels. The rotation consisted of corn, oats, wheat, clover, 

 timothy, and timothy. The other plots have been annually planted to 

 the specific crop mentioned. 



